Policy Based Management technologies represent a potentially important tool in the management of user services provided by web application frameworks. Current policy management systems are, however, a poor fit for the domain due to their lack of support for decentralised management in open environments. The Community Based Policy Management System is a policy framework designed to facilitate management of services in domains where relationships are highly dynamic and flexible, where policy specification is distributed and may use multiple languages, and where management decision-making is shared between communities of users and service providers. This article describes the CBPMS schema and architecture and uses an example to show how it provides flexible, dynamic and extensible policy based management capabilities to the providers of user-services on the web.